View source for Cardia

{{CMG}}



==Overview==
{{Infobox Anatomy |
  Name         = Cardia |
  Latin        = |
  GraySubject  = 247 |
  GrayPage     = 1162 |
  Image        = Illu stomach.jpg |
  Caption      = '''Diagram from [http://training.seer.cancer.gov/ss_module07_ugi/unit02_sec02_anatomy.html cancer.gov]:<BR>'''* 1. [[Body of stomach]]<BR>* 2. [[Fundus (stomach)|Fundus]]<BR>* 3. [[Anterior wall]]<BR>* 4. [[Greater curvature]]<BR>* 5. [[Lesser curvature]]<BR>* 6. Cardia<BR>* 9. [[Pyloric sphincter]]<BR>* 10. [[Pyloric antrum]]<BR>* 11. [[Pyloric canal]]<BR>* 12. [[Angular notch]]<BR>* 13. [[Gastric canal]]<BR>* 14. [[Rugal folds]] |
  Image2       = Gray1046.svg |
  Caption2     = Diagram of the stomach, showing its anatomical landmarks ("Antrum cardiacum" marks the opening of the cardia). |
  Precursor    = |
  System       = |
  Artery       = |
  Vein         = |
  Nerve        = |
  Lymph        = |
  MeshName     = |
  MeshNumber   = |
  DorlandsPre  = c_10 |
  DorlandsSuf  = 12214493  |
}}
{{SI}}
The '''cardia''' (or '''esophagogastric junction''' <ref>{{eMedicineDictionary|esophagogastric+junction}}</ref><ref>{{Dorlands|j_02|12465956}}</ref> or '''gastroesophageal junction''' <ref>{{LoyolaMedEd|Radio/curriculum/GI/Image105b.jpg}}</ref><ref>http://cellbio.utmb.edu/microanatomy/digestive/Esophagus.htm</ref><ref>http://www.cancer.org/docroot/cri/content/cri_2_4_1x_what_is_esophagus_cancer_12.asp?sitearea=cri</ref><ref>http://www.cancer.gov/Templates/db_alpha.aspx?CdrID=302458</ref>) is the [[anatomy|anatomical]] term for the junction orifice of the [[stomach]] and the [[esophagus]]. At the cardia, the [[mucosa]] of the esophagus transitions into [[gastric mucosa]].  

The cardia is also the site of the '''lower esophageal sphincter (LES)'''<ref>http://hopkins-gi.nts.jhu.edu/pages/latin/templates/index.cfm?pg=disease1&organ=1&disease=13&lang_id=1</ref><ref>http://www.physio.unr.edu/ICC/gallery/LES-1.htm</ref><ref>{{eMedicine|med|2965}}</ref> (also termed '''cardiac sphincter'''<ref>{{eMedicineDictionary|cardiac+sphincter}}</ref>, '''gastroesophageal sphincter'''<ref>{{Dorlands|s_18|12748540}}</ref>, and '''esophageal sphincter'''<ref>http://www.mcg.edu/Otolaryngology/patientGERD.htm</ref>).

==Nomenclature and classification==
There is disagreement in the academic anatomy community over whether the cardia is part of the stomach, part of the esophagus or a distinct entity, as described in this article. The difference is more than semantic when used in clinical studies and applied to individual patients. 

Classical [[anatomy]] textbooks, and some other resources<ref>{{Dorlands|c_10|12214493}}</ref><ref>{{SUNYAnatomyLabs|37|06|01|03}} - "Abdominal Cavity: The Stomach"</ref>, describe the cardia as the first of 4 regions of the stomach. This makes sense [[Histology|histologically]] because the mucosa of the cardia is the same as that of the stomach. 

Many recent writings describe it as the LES. 

==Function==
[[Image:Gastro-esophageal jxn.JPG|thumb|left|Microscopic shot of a cross section of human gastro-esophageal junction wall.]]
The stomach generates strong [[acid]]s and [[enzyme]]s to aid in food [[digestion]]. This digestive mixture is called [[gastric juice]]. The inner lining of the stomach has several mechanisms to resist the effect of gastric juice on itself, but the mucosa of the esophagus does not. The esophagus is normally protected from these acids by a one-way valve mechanism at its junction with the stomach. This one-way valve is called the lower esophageal sphincter (LES), and prevents gastric juice from flowing back into the esophagus.

During [[peristalsis]], the LES allows the food [[Bolus (digestion)|bolus]] to pass into the stomach. It prevents [[chyme]], a mixture of bolus, [[stomach acid]], and [[digestive enzyme]]s, from returning up the esophagus. The LES is aided in the task of keeping the flow of materials in one direction by the [[diaphragm (anatomy)|diaphragm]].

==Histology==
On histological examination, the junction can be identified by the following transition:<ref>{{BUHistology|11101loa}}</ref><ref>{{BUHistology|11111ooa}}</ref>

* nonkeratinized [[stratified squamous epithelium]] in the [[esophagus]]
* [[simple columnar epithelium]] in the [[stomach]]

However, in [[Barrett's esophagus]], the epithelial distinction may vary, so the histological border may not be identical with the functional border.

The [[cardiac glands]] can be seen in this region. They can be distinguished from other stomach glands ([[fundic glands]] and [[pyloric glands]]) because the glands are shallow and simple [[tubular glands|tubular]].

==Pathology==
Deficiencies in the strength or the efficiency of the LES lead to various medical problems involving acid damage on the esophagus. 

In [[achalasia]], one of the defects is failure of the LES to relax properly.
















==Etymology==
The word comes from the [[Greek language|Greek]] ''kardia'' meaning ''heart'', the cardiac orifice of the stomach.

==Additional images==
<gallery>
 Image:Gray1050.png
 Image:Gray1053.png|Section of mucous membrane of human stomach, near the cardiac orifice. X 45.
</gallery>

==References==
<references/>


{{Digestive tract}}

[[Category:Abdomen]]
[[Category:Digestive system]]

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